1. Field of Invention
This invention relates to increasing aircraft safety during emergency landings, specifically to an improved system of aircraft capture, fire suppression and braking via strict movement control during the event.
2. Description of Prior Art
It is increasingly common for aircraft to make emergency landings due to various factors. Some common events include: hydraulic failure which can dramatically reduce control of an aircraft, landing gear deployment failure and fire involving either interior or exterior fuselage components. During these emergencies, it is imperative that the incoming aircraft be greeted with a landing system employing as many safety features as can be assembled.
For a great number of years, the only options that have been available as a matter of practice are hard landings (aircraft vs. runway) and foaming of the runway surface. These contain significant drawbacks as fuselage damage occurs and the consequent sparking produces fires. Over the course of the past few years, other devices have been proposed. U.S. Pat. No. 4,653,706 to Ragiab (1987) shows a rolling bed propelled by battery power. There is a significant need for a number of batteries, which create acceleration drag. The system is also operated by remote control which is weather-bound. The system may be unable to deploy when rain or snow reduces visibility to near zero. There is also a significant possibility of the capture unit leaving the runway surface as the tires can slide on a slippery runway. Attempting to deploy such a system in high wind can create difficulties in getting said unit to the desired runway.
Another aircraft landing safety system embodied in U.S. Pat. No. 5,170,966 to Sheu (1992) shows a system operated in dedicated space. There is significant loss of landing area with such a system. Airport runway use is restricted by taking a strip of land out of service for this landing system. It is also restricted for use by weather conditions. Snow and ice can seize the exposed rollers designed to move the sled forward and perform consequent braking functions. An all-weather system is necessary to be effective in emergency landing situations all over the world.
Other systems include cables stretched across a runway surface with the purpose of snagging an aircraft to bring it to a stop. This creates a severe jolt for both passengers and the aircraft structure. The result can be injury and catastrophic damage to the aircraft. A U.S. Pat. No.5,560,568 by Schmittle (1996) details a specially designed aircraft that can land vertically on an air bag. This is a specific method of landing an aircraft that is not practical for existing aircraft in that it would require tremendous aircraft redesign. The expense would be prohibitive.
The aircraft emergency landing systems named heretofore and others from the past suffer from a number of disadvantages:
(a) Prior systems developed are restricted to fair weather operation. Airports located in northern climates require an emergency landing system that can operate in severe cold and in ice and snow conditions. PA1 (b) Some systems require the use of space that eliminates the use of such space for normal runway operations. Airports in many areas are strapped for land use and can not take an area out of service. PA1 (c) The use of any system that does not take into account the force of physics on an aircraft landing at an angle can cause the system to leave a runway surface. This can produce injury to passengers and aircraft damage; the very problems that the system seeks to correct. PA1 (d) Fire suppression on other systems is limited to the runway surface. An aircraft landing upon a sled of some type may need immediate fire suppression upon the aircraft exterior. The time that passes between aircraft recovery and movement cessation is time that can be used to extinguish engine fires. PA1 (e) The capture of an aircraft potentially weighing 80 tons plus requires rapid acceleration and braking of the recovery unit. Systems that require the aircraft to strike a stationary system first or that require a long runway acceleration period for the recovery unit place the mission in jeopardy. Matching incoming aircraft speed to recovery unit ground speed is critical. PA1 (a) to provide an emergency landing system that is fully operational in all weather conditions; PA1 (b) to provide stability in the recovery and braking of an aircraft landing under emergency circumstances; PA1 (c) to provide exceptional speed and braking forces to capture and brake an aircraft making an emergency landing; PA1 (d) to provide fire suppression to the exterior of an aircraft during the critical moments between aircraft capture and completed braking; PA1 (e) to provide an emergency landing system that allows for the normal operation of the runway in which it is installed and yet, maintain the ability for immediate emergency deployment; PA1 (f) to provide a means for aircraft to recovery unit contact that is aided by instrumentation for landing accuracy; PA1 (g) to provide a backup propulsion and braking system for additional operational safety; PA1 (h) to provide a system of recovery cells on the surface of the recovery unit that can maintain critical aircraft stability upon aircraft capture despite damage to cells.